the point of a AWD system is to get results down on paper... ultimately RWD is best... but on street tires on the street.... AWD is a little superior in everyday activity's....

or if your like Mitsu or Subaru to go race the WRC...

AWD is clearly more important when the wheels CAN break loose and this is at take offs and low speed. Clearly the combination of AWD, LC and DCT make the GT-R a 0-60 rocket.

Why don't road race cars use AWD? Power to the front wheels would reduce the amount of their ultimate grip level that can be applied to create the maximum cornering load. This is one big part. The other is that at most track speeds, on straights, most RWD cars simply don't have enough power to spin the wheels at will. Of course weight and complexity and drive train losses play a role as well.